Who is president if the president is removed from office?

Answer 1

The President can remove nearly any Executive Branch appointee, including cabinet officers. That is why they have the mantra "I serve at the pleasure of the President." Note, as an elected officer, the Vice President is not subject to removal by the President.

The exceptions are certain Congressionally-specified Executive Branch agencies which have leaders appointed for fixed terms. Generally, those agencies are supposed to be "non-partisan" agencies, such as the Securities Exchange Commission, or which should be explicitly insulated from political influence, such as the FBI. The other primary exception is Administrative Law Judges, which are part of the Executive Branch, not the Judicial Branch. These judges may not be removed from office by the President. All of the aforementioned positions may be removed from office via various means, but not at the sole discretion of the President.

As Commander in Chief of the US Armed services, the President has the power to reassign ANY member of the Armed Services from their current post, though they may not demoted or forced out of the military without appropriate administrative action (e.g. Court Martial or similar disciplinary action). The President may not promote officers to General (or equivalent) or higher rank without permission from Congress.

No member of the Judicial or Legislative Branch may be removed by the President.

Of course, most non-appointed government employees are protected from removal, except for criminal offenses, by civil service regulations.

Answer 2

The House of Representatives votes to impeach, and the Senate holds the trial and votes whether to remove him/her from office.

Answer 3

The vice president.